1. Field of the Invention
The present invention relates to a process for producing an ohmic electrode for n-type cubic boron nitride.
2. Prior Art
Hitherto, for producing an electrode for a semiconductor cubic boron nitride (hereafter referred to as "cBN"), a silver paste is used as described in Appl. Phys. Lett., vol 53 (11), Sep. 12, 1988, pp. 962.about.964, but the actual technique for producing an ohmic electrode for a semiconductor cBN has not yet been developed at present.
In a conventional process for producing an electrode using a silver paste, the contact resistance is large and also the resistance characteristics of the passing electric current are unstable. Furthermore, a silver paste displays a poor wetting property to cBN, in addition to the problem the adhesive strength is weak, whereby the electrode is liable to be separated from the crystal. Accordingly, it is difficult to produce a semiconductor using a cBN crystal.
On the other hand, an ohmic electrode for p-type cBN is described in Japanese patent application No. 1-276346.